#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <queue>
#include <stack>
#include <vector>

using namespace std;

struct ListNode {
    int val;
    ListNode* next;
    ListNode(int x) : val(x), next(NULL) {}
};

class Node {
   public:
    int val;
    Node* next;
    Node* random;

    Node(int _val) {
        val = _val;
        next = NULL;
        random = NULL;
    }
};

struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
    bool helper(TreeNode* l, TreeNode* r) {
        if (l == NULL && r == NULL) {
            return true;
        }
        if (l == NULL || r == NULL) {
            return false;
        }
        return l->val == r->val && helper(l->left, r->right) &&
               helper(l->right, r->left);
    }

   public:
    bool isSymmetric(TreeNode* root) {
        if (root == NULL) {
            return true;
        }
        return helper(root->left, root->right);
    }
};

int main() {
    cout << "Hello, World!";
    // Solution()
    return 0;
}
